<template>
  <div class="child">
    <h2>child ---{{ msg }}</h2>
    <button @click="handleChangeMsg">handleChangeMsg</button>
  </div>
</template>
<script>
export default {
  props: ['msg'],
  data() {
    return {}
  },
  methods: {
    handleChangeMsg() {
      this.$emit('update:msg', '更新了')
    },
  },
}
</script>
<style
  lang="scss"
  scoped
></style>
